Meta-analysis of the association between preterm delivery and intelligence

Kerr-Wilson, C.O., Mackay, D.F. , Smith, G.C.S. and Pell, J.P. (2012) Meta-analysis of the association between preterm delivery and intelligence. Journal of Public Health, 34(2), pp. 209-216. (doi: 10.1093/pubmed/fdr024)

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<p>Background An increasing proportion of infants are born preterm, and their survival has improved. Therefore, their long-term sequelae</p> <p>Methods We conducted a systematic review covering a 30 year period (1980–2009). A random effects meta-analysis provided a pooled estimate of the difference in IQ score between individuals born preterm and term. Small-study bias was examined using a funnel plot and Egger's test, and meta-regression was used to investigate possible causes of heterogeneity. Cumulative meta-analysis was used to determine if the magnitude of the association had changed over time.</p> <p>Results The 27 eligible studies covered 7044 individuals; 3504 (50%) delivered preterm and 3540 (50%) at term. They provided 37 estimates of difference in IQ. All demonstrated a reduced IQ among those delivered preterm and all but four reached statistical significance. Overall, IQ score was 11.94 (95% CI: 10.47–13.42, P < 0.001) points lower among children born preterm. There was moderate heterogeneity (overall I2 74.2%, P < 0.001), but no significant small-study bias (P = 0.524). The association between preterm delivery and IQ did not change significantly over time. There was a statistically significant, linear association across the gestational age range (adjusted coefficient: −0.91, 95% CI: −1.64, −0.17, P = 0.018).</p> <p>Conclusions There is a strong and consistent body of evidence suggesting an association between preterm delivery and reduced IQ, with evidence of a dose–response relationship with gestational age.</p>

Item Type:Articles
Glasgow Author(s) Enlighten ID:Pell, Professor Jill and Mackay, Professor Daniel
Authors: Kerr-Wilson, C.O., Mackay, D.F., Smith, G.C.S., and Pell, J.P.
College/School:College of Medical Veterinary and Life Sciences > Institute of Health and Wellbeing > Public Health
Journal Name:Journal of Public Health
Publisher:Oxford University Press
ISSN (Online):1741-3850
Published Online:09 March 2011

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